TBL small break test analyses by new LOCA analysis codes

Through the various safety researches on BWR plants over past several years, the major and key phenomena of LOCA in BWRs have been clarified. These phenomena play an important role in core reflooding. Based on the physical understanding of the LOCA phenomena in BWRs, new BWR LOCA analysis codes, SAFER 02 and TRAC-BD1, have been developed. SAFER 02 is a one-dimensional thermal hydraulic code for the long term inventory analysis of LOCA in BWRs. TRAC-BD1 is a best estimate system code developed at Idaho National Engineering Laboratory for BWR LOCA analysis. This code features the three-dimensional treatment of pressure vessels and the one-dimensional treatment of other components of reactors. The thermal hydrodynamic model is a heterogeneous, non-equilibrium two-fluid formulation of two-phase flow. The simulation test on the small break LOCA in a BWR was carried out in the two bundle loop. A small break test was used to demonstrate the ability of both SAFER 02 and TRAC-BD1 codes to predict the realistic behavior of BWRs in small break LOCA. The test analysis was carried out for the qualification of both codes. The TBL facility and the test results, the analytical models and conditions, and the analytical results are reported. (Kako, I.)